package com.kellyfeng.account.persist;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.List;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.DocumentFactory;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;

public class AccountPersistServiceImpl implements AccountPersistService {
	private static final String ELEMENT_ROOT = "account-persist";
	private static final String ELEMENT_ACCOUNTS = "accounts";
	private static final String ELEMENT_ACCOUNT = "account";
	private static final String ELEMENT_ACCOUNT_ID = "id";
	private static final String ELEMENT_ACCOUNT_NAME = "name";
	private static final String ELEMENT_ACCOUNT_EMAIL = "email";
	private static final String ELEMENT_ACCOUNT_PASSWORD = "password";
	private static final String ELEMENT_ACCOUNT_ACTIVATED = "activated";

	private String file;

	private SAXReader reader = new SAXReader();

	public String getFile() {
		return file;
	}

	public void setFile(String file) {
		this.file = file;
	}

	public Account createAccount(Account account) throws AccountPersistException {
		Document doc = readDocument();

		Element accountsEle = doc.getRootElement().element(ELEMENT_ACCOUNTS);

		accountsEle.add(buildAccountElement(account));

		writeDocument(doc);

		return account;
	}

	@SuppressWarnings("unchecked")
	public void deleteAccount(String id) throws AccountPersistException {
		Document doc = readDocument();

		Element accountsEle = doc.getRootElement().element(ELEMENT_ACCOUNTS);

		for (Element accountEle : (List<Element>) accountsEle.elements()) {
			if (accountEle.elementText(ELEMENT_ACCOUNT_ID).equals(id)) {
				accountEle.detach();

				writeDocument(doc);

				return;
			}
		}
	}

	@SuppressWarnings("unchecked")
	public Account readAccount(String id) throws AccountPersistException {
		Document doc = readDocument();

		Element accountsEle = doc.getRootElement().element(ELEMENT_ACCOUNTS);

		for (Element accountEle : (List<Element>) accountsEle.elements()) {
			if (accountEle.elementText(ELEMENT_ACCOUNT_ID).equals(id)) {
				return buildAccount(accountEle);
			}
		}

		return null;
	}

	public Account updateAccount(Account account) throws AccountPersistException {
		if (readAccount(account.getId()) != null) {
			deleteAccount(account.getId());

			return createAccount(account);
		}

		return null;
	}

	private Account buildAccount(Element element) {
		Account account = new Account();

		account.setId(element.elementText(ELEMENT_ACCOUNT_ID));
		account.setName(element.elementText(ELEMENT_ACCOUNT_NAME));
		account.setEmail(element.elementText(ELEMENT_ACCOUNT_EMAIL));
		account.setPassword(element.elementText(ELEMENT_ACCOUNT_PASSWORD));
		account.setActivated(("true".equals(element.elementText(ELEMENT_ACCOUNT_ACTIVATED)) ? true : false));

		return account;
	}

	private Element buildAccountElement(Account account) {
		Element element = DocumentFactory.getInstance().createElement(ELEMENT_ACCOUNT);

		element.addElement(ELEMENT_ACCOUNT_ID).setText(account.getId());
		element.addElement(ELEMENT_ACCOUNT_NAME).setText(account.getName());
		element.addElement(ELEMENT_ACCOUNT_EMAIL).setText(account.getEmail());
		element.addElement(ELEMENT_ACCOUNT_PASSWORD).setText(account.getPassword());
		element.addElement(ELEMENT_ACCOUNT_ACTIVATED).setText(account.isActivated() ? "true" : "false");

		return element;
	}

	private Document readDocument() throws AccountPersistException {
		File dataFile = new File(file);

		if (!dataFile.exists()) {
			dataFile.getParentFile().mkdirs();

			Document doc = DocumentFactory.getInstance().createDocument();

			Element rootEle = doc.addElement(ELEMENT_ROOT);

			rootEle.addElement(ELEMENT_ACCOUNTS);

			writeDocument(doc);
		}

		try {
			return reader.read(new File(file));
		} catch (DocumentException e) {
			throw new AccountPersistException("Unable to read persist data xml", e);
		}
	}

	private void writeDocument(Document doc) throws AccountPersistException {
		Writer out = null;

		try {
			out = new OutputStreamWriter(new FileOutputStream(file), "utf-8");

			XMLWriter writer = new XMLWriter(out, OutputFormat.createPrettyPrint());

			writer.write(doc);
		} catch (IOException e) {
			throw new AccountPersistException("Unable to write persist data xml", e);
		} finally {
			try {
				if (out != null) {
					out.close();
				}
			} catch (IOException e) {
				throw new AccountPersistException("Unable to close persist data xml writer", e);
			}
		}
	}
}
